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An archive containing lots of small files could trigger an error even though the amount of decompressed data was way below the maximum allowed size. This happened because the decompression algorithm used the chunk size for calculating the remaining size instead of the actual size of the decompressed chunk.
97 lines
2.7 KiB
Ruby
97 lines
2.7 KiB
Ruby
# frozen_string_literal: true
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module Compression
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class Strategy
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ExtractFailed = Class.new(StandardError)
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DestinationFileExistsError = Class.new(StandardError)
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def can_handle?(file_name)
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file_name.include?(extension)
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end
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def decompress(dest_path, compressed_file_path, max_size, allow_non_root_folder: false)
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sanitized_compressed_file_path = sanitize_path(compressed_file_path)
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get_compressed_file_stream(sanitized_compressed_file_path) do |compressed_file|
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available_size = calculate_available_size(max_size)
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entries_of(compressed_file).each do |entry|
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entry_path = build_entry_path(
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compressed_file, sanitize_path(dest_path),
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sanitized_compressed_file_path, entry,
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allow_non_root_folder
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)
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if is_file?(entry)
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remaining_size = extract_file(entry, entry_path, available_size)
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available_size = remaining_size
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else
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extract_folder(entry, entry_path)
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end
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end
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end
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end
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def strip_directory(from, to, relative: false)
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sanitized_from = sanitize_path(from) rescue nil
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sanitized_to = sanitize_path(to) rescue nil
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return unless sanitized_from && sanitized_to
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glob_path = relative ? "#{sanitized_from}/*/*" : "#{sanitized_from}/**"
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FileUtils.mv(Dir.glob(glob_path), sanitized_to) if File.directory?(sanitized_from)
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end
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private
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def sanitize_path(filename)
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Pathname.new(filename).realpath.to_s
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end
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# https://guides.rubyonrails.org/security.html#file-uploads
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def sanitize_filename(filename)
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filename.strip.tap do |name|
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# NOTE: File.basename doesn't work right with Windows paths on Unix
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# get only the filename, not the whole path
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name.sub! /\A.*(\\|\/)/, ''
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# Finally, replace all non alphanumeric, underscore
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# or periods with underscore
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name.gsub! /[^\w\.\-]/, '_'
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end
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end
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def calculate_available_size(max_size)
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1024**2 * (max_size / 1.049) # Mb to Mib
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end
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def entries_of(compressed_file)
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compressed_file
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end
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def is_file?(entry)
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entry.file?
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end
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def chunk_size
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@chunk_size ||= 1024**2 * 2 # 2MiB
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end
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def extract_file(entry, entry_path, available_size)
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remaining_size = available_size
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if ::File.exist?(entry_path)
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raise DestinationFileExistsError, "Destination '#{entry_path}' already exists"
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end
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::File.open(entry_path, 'wb') do |os|
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while (buf = entry.read(chunk_size))
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remaining_size -= buf.size
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raise ExtractFailed if remaining_size.negative?
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os << buf
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end
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end
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remaining_size
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end
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end
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end
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